Setting a Loopback for a PDH Interface (RTN NEs)

You can set a loopback for a PDH interface by using the U2000 Web LCT. The PDH interface loopback is a common fault location method used to test and maintain the PDH board. The PDH interface loopback is used to test the fiber connections and interfaces on the PDH board, and is also used to test the PDH service processing module and the cross-connect board.

Context

The PDH interface loopback can be set to an outloop or an inloop.

When an outloop is used, the PDH signal received by the NE is returned at the PDH interface. See Figure 1. An outloop is used to test the fibers connections and interfaces on the PDH board.
Figure 1 Outloop
When an inloop is used, the PDH signal transmitted by the NE is returned to the cross-connect board at the PDH interface. See Figure 2. An inloop is used to test the PDH service processing module and the cross-connect board.
Figure 2 Inloop

NOTICE:

As a loopback interrupts services, it is only used for fault location and must be released after the fault is removed.

NOTE:

The methods of performing a loopback for a PDH interface on U2000 Web LCT varies according to different board type. Please choose from the following two methods.

Procedure

Navigation Path 1:
1. In the NE Explorer, select a board and choose Configuration > PDH Interface from the Function Tree.
2. Select By function and select Tributary Loopback.
3. Select a PDH interface from the list and double-click Tributary Loopback to choose the loopback mode.
Navigation Path 2:
1. In the NE Explorer, select a board and choose Configuration > Interface Management > PDH Interface from the Function Tree.
2. Click Advanced Attributes tab. Select a PDH interface from the list and set the value of Loopback Mode.
Click Apply, the dialog box dispalyed indicating this operation may interrupt service.
Click OK. A prompt is displayed indicating that the operation is successful.
Click Close.